Mitsubishi Electric MSZ-LN25VGW Service Manual page 22

10-2. FAILURE MODE RECALL FUNCTION
Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though LED indication listed on the troubleshooting check table (10-4.) disappears, the memorized failure details
can be recalled.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Operational procedure
The cause of abnormality cannot be found because the abnormality does not recur.
Setting up the failure mode recall function
Turn ON the power supply.
<Preparation of the remote controller>
While pressing both OPERATION SELECT button and TEMP
controller at the same time, press RESET button.
First, release RESET button.
Hold down the other two buttons for another 3 seconds. Make sure that the indicators
on the LCD screen shown in the right fi gure are all displayed. Then release the but-
tons.
The set temperature is displayed to 24°C.
Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is
displayed) with the remote controller headed towards the indoor unit.
Does POWER lamp on the indoor unit blink at the
interval of 0.5 seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing as the
blinking of POWER lamp.*2
Judgment of indoor/outdoor abnormality
Before blinking, does POWER lamp stay ON for
3 seconds?
When it stays ON for 3 seconds (without beep):
The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the
table of indoor unit failure mode recall function. (Refer to 10-2.4)
Make sure to check at least 2 consecutive blinking cycles.
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall
function" mentioned above.
Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is displayed)
with the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted. *4
Release the failure mode recall function according to "Releasing the failure mode recall function" men-
tioned above.
NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.
2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
*2. Blinking pattern when the indoor unit is abnormal:
2.5-second OFF
ON
OFF
Repeated cycle
*3.Blinking pattern when the outdoor unit is abnormal:
2.5-second OFF
ON
OFF
OBH766
1 Regardless of normal or abnormal condition,
*
a short beep is emitted once the signal is
received.
Yes
(Blinks)
The outdoor unit is abnormal.
No
2
*
Repair the failure parts.
Blinking at 0.5- Blinking at 0.5-
second interval second interval
2.5-second OFF
Beeps
Repeated cycle
Blinking at 0.5-
3-second ON
second interval
No beep Beeps
Repeated cycle
NOTE: The indoor unit does not operate by smartphone, but when it operates by remote
controler, refer to 10-3.2."Check of Wi-Fi Interface".
button on the remote
1
*
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnor-
malities that cannot be recalled with this way.
No
Check if outdoor unit is abnormal according to the detailed outdoor unit
(OFF)
failure mode recall function.
NOTE: It takes up to 1 minute to indicate the outdoor unit abnormality.
Even if the OPERATION INDICATOR lamp is not lighting, keep
checking at least 1 minute or longer.
Yes
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring
to the table of ondoor unit failure mode recall function. (Refer to outdoor
unit service manual.)
Make sure to check at least 2 consecutive blinking cycles.*3
Beeps
Beeps
Repeated cycle
2.5-second OFF 3-second ON
No beep
Repeated cycle
22
*4 The information regarding whether the connected
outdoor unit is a low-standby-power model or a non-
low-standby-power model will also be initialized.
(Default= compatible with a low-standby-power model)
Blinking at 0.5-
second interval
Beeps
Repeated cycle